In the manufacturing process of a semiconductor device, the quality of the device is determined by testing an electric characteristic of each integrated circuit chip of a wafer after the chips are completed. Such a test is performed by a test apparatus called a probe apparatus including: a main body in which a mounting table for mounting, e.g., a semiconductor wafer is provided; a probe card installed in a head plate (ceiling plate) of the main body and having probes provided at its bottom surface, the probes being brought into contact with electrode pads of a chip; and a box-shaped test head provided above the probe card and connected to the probe card via a pogo ring having pogo pins in its top and bottom surfaces.
In a typical structure for installing the test head, a pivot mechanism having a rotation shaft, which is rotatable about a horizontal axis, is provided at a side of the main body of the probe apparatus and the test head is supported at its side by an arm extending from the rotation shaft. The test head is pivotable from a horizontal position toward its back surface at an upper side of the probe apparatus.
Since the probes of the probe card are arranged according to the electric pads of chips, it is required to exchange the probe card depending on kinds of wafers to be tested. Accordingly, there has been suggested a structure in which the probe card is held by a card holder and an elevation mechanism is provided to move the card holder upward and downward. When a wafer is tested, the probe card is moved upward to press the pogo ring of the test head. When the probe card is exchanged, the probe card is moved downward and separated from the pogo ring and then the probe card is drawn out from an outer side of the main body by sliding the card holder aside. When the probe card is exchanged, the test head remains its horizontal posture. However, in the maintenance, the test head is pivoted and separated from the head plate. When the maintenance is finished, the test head returns to the horizontal posture.
A regular load is required to make sure the electrical contact between the pogo ring and the probe card. To apply the load, it is necessary to push the test head relatively downward (or to push the probe card relatively upward) by, e.g. about 2 mm after the test head is brought into contact with the probe card. However, it is very difficult and unrealistic to move the heavy test head downward by such a fine amount by using a mechanism provided for the test head. Accordingly, as described above, the elevation mechanism is provided at the card holder to acquire the fine elevation amount.
The above probe apparatus, however, requires the mechanisms for sliding the card holder aside and moving the card holder upward and downward, which increases the cost of the probe apparatus. Alternatively, when the test head is separated from the head plate, an operator may exchange the probe card to the upper surface of the head plate. In this case, since it is necessary to accurately move the card holder upward by a fine amount in a state where the card holder is mounted to the head plate, a complex elevation mechanism is needed.
Such test apparatuses have been disclosed in, e.g., Japanese Patent Laid-open Applications Nos. H03-022546 and H02-177343. Further, e.g., Japanese Patent Laid-open Applications Nos. H01-272982 (FIG. 1) and H10-050778 (FIG. 2)), disclose mechanisms for accurately aligning the positions of the test head and the wafer or for horizontally holding the test head. However, any consideration related to the aforementioned issue is not reflected to the above patent documents.